The Scientific Method

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The Scientific Method
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Scientific Process

• Problem or Question
• Gather information
• Hypothesis (prediction)
• Experimentation
• Conclusions

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Observations and Questions

• People jump back when they see a large dog.
• Why are people afraid of large dogs.
• People are afraid of large dogs because TV and
  the Media often portray large dogs as vicious and
  mean.

• Science is ultimately based on observation
• Observations often lead to questions ---gt which
  lead to experiments to answer the questions

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Hypothesis

• a testable statement, can be shown to be true or
  false by experimenting or observation

Good Bad
1. Plants will grow taller when given Miracle Grow 1. Plants will grow better when given Miracle Grow.
2.Girls will score higher on math tests than boys 2. Girls are smarter than boys.
3. Hermit crabs choose colorful shells over drab shells. 3. Hermit crabs like colorful shells
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Experiment

• Experimentation - a planned procedure designed to
  test the hypothesis.
• Experimental Group -receives some kind of
  treatment or condition
• Control Group - receives no treatment, used to
  compare

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Example of an experimental design

• Hypothesis Plants will grow taller when given
  Miracle Grow.
• Plants A B are both given the same amount of
  light, water, and are stored at the same
  temperature. Plant A is given Miracle Grow.
• All the variables are kept constant except the
  one you are testing.

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Variables

• Independent Variable - the factor you change,
  what you do to your exp. group. (Miracle Grow)
• Dependent Variable - what happens as a result of
  that treatment, what you are measuring (height of
  plant)

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Practice

• In an experiment, a goldfish is placed in a 15
  gallon tank. Another goldfish is placed in a 50
  gallon tank.  The experimenter feeds them exactly
  the same amount of food and weighs them one year
  later to see which one grew the most.
•  
• What is the independent variable in this
  experiment?
•  
• What is the dependent variable? 

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Collecting Data

• Data should always be presented in a neat
  fashion, usually tables or graphs

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Conclusions

• Based on the data, a scientist then determines
  whether the hypothesis was supported or refuted.
  Science is subject to change when new evidence is
  found. While experimentation and observations
  can provide strong evidence for a conclusion, it
  is not absolute proof

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Taking it one step further

• Theory- well tested explanation that unifies a
  set of observations
• Theory of Evolution
• How are a Theory and a Hypothesis different?????

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Homework Pick a Question and Design an Experiment

• 1.  Will human urine repel sharks?
• 2.  Does the color red make lizards more
  aggressive?
• 3.  Will fish grow larger if placed in a larger
  tank?
• 4.  Does exercise reduce your risk of heart
  attack?
• 5.  Does aspirin keep cut flowers fresh longer?

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How to Display Data

• WHEN TO USE GRAPHS AND HOW TO CHOOSE THE RIGHT
  TYPE OF GRAPH

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Examples of Graphs

• Line graph

• Bar Graph

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Examples of Graphs

• Pie charts

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Line Graph

• A line graph is most useful in displaying data or
  information that changes continuously over time.

Date Temperature
1 10
2 25
3 30
4 42
5 23
6 25
7 40
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Bar Graph

Activity Number
Visit W/Friends 175
Talk on Phone 168
Play Sports 120
Earn Money 120
Use Computers 65

• Bar graphs are an excellent way to show results
  that are one time, that aren't continuous -
  especially samplings such as surveys,
  inventories, etc.

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Pie Charts

• Circle or pie graphs are particularly good
  illustrations when considering how many parts of
  a whole are inception.

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Graph Quiz Tommorow

• YOU WILL HAVE A QUIZ ON GRAPHING TOMORROW !
• DONT WORRY WE ARE GOING TO PRACTICE YOUR
  GRAPHING SKILLS.